.google-calendar-xblock-wrapper{
    position: relative;
    padding-bottom: 56.25%; /* 16:9 */
    padding-top: 25px;
    height: 0;
}

.google-calendar-xblock-wrapper iframe{
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}
